This invention has relation to chutes for feeding and conveying ammunition cartridges during manufacture, packaging, loading into clips or magazines or the like for use or storage and directly into guns for firing.
Vertical movement by gravity through chutes which maintain the cartridges to have longitudinal axes in horizontal alignment can be achieved relatively easily if the chutes are run full at all times. However, whenever cartridges are put into an empty or partially empty chute, or otherwise allowed to fall free, they tend to move out of horizontal alignment and to jam in the chute. Often this necessitates at least pushing the cartridges from above to force horizontal realignment until the chute is full and each cartridge rests on the one below to insure substantially horizontal alignment.
The ever increasing period of cartridge manufacturing processes, along with the use of automatic weapons, has increased the need for rapid and reliable means for feeding and transferring large numbers of ammunition cartridges. Cartridges must be handled carefully in view of possible accidential discharge or damage causing failure or erratic discharge from a weapon.
Early feeding mechanisms fed cartridges upward to the firing position using a leaf spring. Such an arrangement is shown in U.S. Pat. No. 1,306,972 to C. A. Nelson, granted June 17, 1919. Refinements include the addition of padding to protect the cartridge projectile and casing. See for example U.S. Pat. Nos. 1,370,617 to J. T. Thompson, granted on Mar. 8, 1921, and U.S. Pat. No. 2,745,203 granted to C. B. Ruple on May 15, 1956.
A device for loading magazines operable in any direction is shown in U.S. Pat. No. 2,659,173 to G. D. Capito, granted on Nov. 17, 1953. A casing 18 snuggly encloses shell S except for the forward end of detonator cap 19 and percussion cap 20. The cartridges are fed by sliding a pusher plate 26.
The prior art includes chutes or clips which feed cartridges downwardly yet rely on means other than gravity. In U.S. Pat. No. 2,834,137 to W. R. Kunz, granted May 13, 1958, a magazine charger has a transverse cross section similar to the longitudinal profile of the cartridges. The cartridges are fed by pressure from the operator's thumb against the top cartridge of the charger, forcing the column downward against a spring. U.S. Pat. No. 3,222,810 to D. D. Musgrave, granted Dec. 14, 1965 discloses a loading clip which retains cartridges in a staggered column. A member 11 is moved downward against the top cartridge to force the bottom cartridge out of the clip against the force of lips 21.
Plastic stackable U-shaped chutes are disclosed in U.S. Pat. No. 2,284,488 to F. C. Johnson granted May 26, 1942. The cartridges fed through each chute are held together by a belt 20. Ribs 16 and 18 support the cartridges and reduce friction as the cartridge belt slides through a particular chute.
One method of positioning cartridges in a chute, particularly those having an extractor groove, is to provide means extending into the extractor groove to limit longitudinal and lateral movement of the cartridge. One example of this is seen in the Musgrave patent at 9 and 37 in FIG. 9.
One method of gravitional feeding utilizes an upright chute containing cartridges in a single vertical column, each cartridge having its longitudinal axis horizontally aligned. This method is operable so long as the chute remains filled, each cartridge supported in horizontal alignment by the one beneath it. When a cartridge experiences free fall, however, as when it enters an empty or partially filled chute, it tends to fall out of horizontal alignment and jam in the chute. Mechanical means for urging jammed cartridges downward in the chute are expensive and in most instances impractical. The alternative is pre-priming, or filling each chute by hand before its connection into a manufacturing system. Pre-priming is inconvenient, time consuming, and costly in view of present manufacturing techniques.